How to Overwinter Begonias

Begonias give you months of colour for very little effort — and then one cold night flattens them. The good news: most begonias are only tender, not truly annual. With half an hour of work in autumn you can save this year's plants and start next season with bigger, stronger, free begonias. The right method depends entirely on which type you're growing, so start there.

First, know which begonia you have

• Tuberous begonias (large, rose-like flowers; dies back completely): overwinter as a dormant tuber in a box — the classic method this guide focuses on.
• Fibrous or wax begonias (small flowers, waxy leaves, fibrous roots): no tuber to store — bring them indoors and grow them as winter houseplants.
• Rhizomatous and cane begonias (grown for foliage, like Begonia rex or angel-wings): treat as houseplants year-round; they never need lifting.
• Hardy begonias (Begonia grandis): survive winter in the ground in milder regions under a thick mulch.

Tip: tip your begonia out of its pot in doubt — a flattened, cork-like disc under the stem means tuberous. Or photograph it in PlantMe and let the app identify the type for you.

When to lift tuberous begonias

Timing is a balance: the longer the foliage stands, the more energy flows back into the tuber — but a hard freeze can ruin it. The classic approach is to wait until the first light frost blackens the top growth, then lift within a few days, well before the ground freezes. From late summer you can help the plant wind down by gradually reducing watering and stopping feeding altogether.

Lifting and curing, step by step

• Cut the stems back to about 2–3 cm above the tuber.
• Lift the whole root ball with a fork, keeping a margin around the stem so you don't spear the tuber.
• Brush off the worst of the soil — don't wash the tuber, and don't peel off the skin.
• Lay the tubers out in a single layer somewhere cool, dry and airy for about two weeks to cure. They're ready when the remaining stem stubs are dry and detach with a gentle twist.

Warning: the stub is the danger zone. If you snap green stems off flush with the tuber, you open a wet wound that invites rot in storage. Let curing loosen the stubs naturally.

Storing tubers through winter

Nest the cured tubers in a cardboard box or paper bag filled with barely-damp-to-dry sawdust, vermiculite or coir, so they don't touch each other. Store at roughly 5–10°C — a frost-free garage, cellar or unheated spare room is ideal. Check monthly through winter: discard anything soft or mouldy, and if tubers look shrivelled, very lightly mist the packing material.

Overwintering wax begonias indoors

Fibrous-rooted begonias just keep growing if you let them. Before the first frost, cut the plants back by about half, pot them into fresh, free-draining compost, check carefully for pests (especially under the leaves), and put them on a bright windowsill out of cold draughts. Water only when the top few centimetres of soil are dry — winter overwatering is the main way these plants die indoors. Come spring, harden them off over a week and plant them back out after the last frost.

Waking tubers up in spring

In early-to-mid spring, set tubers hollow-side up in trays of moist compost, barely covered, at around 18°C in good light. Once shoots reach a few centimetres, pot them individually. Wait until all frost risk has passed before they go back outside — begonias have no tolerance for a late cold snap.